From how this looks, it appears to be a POSIX environment within which the shell commands, and git, will run. Something not unlike the ixemul solution (GeekGadgets, ADE, etc.) for the Amiga.

The "git" command sits next to this repository and it appears that it's the genuine article, although quite a bit behind the currently stable master version. Because it was forked off the original Git, it needs a working Perl setup.

It appears that this is a dead-end

A feature-complete Git client for the Amiga still seems to require more work. Sebastian Bauer has been working on it (https://sonumina.de/jenkins/job/sgit.amiga/), but so far it seems it is available only for AmigaOS4 and a plain 68k version is not provided.